There is a behavior therapy that uses the principle of classical conditioning that stood out to me. It is called Aversion therapy so this is a form of treatment that causes patients to be exposed to a stimulus while being simultaneously subjected to some form of discomfort. This means that a patient has to give up an undesirable habit by causing them to associate it with an unpleasant effect. The first version of this treatment was when Roman writer Pliny the Elder found that people were addicted to wine. So Ply the Elder thought that if you would put a large spider at the bottom of the wine glass people would automatically be traumatized by the bug. So the next time they pick up a wine glass you would only think about the spider and that would cause you to never drink wine again.
So with this therapy, I feel like a lot of people have done this but not in that type of extreme way like how when mothers try to wean off their babies from drinking from the bottle or having a pacifier in their mouth all the time. I have seen mothers first put hot sauce on the bottle or pacifier and the child might even like and continue to drink or hate it and never drink again. Then I have seen mothers put maybe lemon juice on the pacifier and the child automatically makes this extreme sour face and never touches it again because they only associate the lemon juice with the pacifier. I think it's so interesting how people can just stop doing a habit just from this one traumatic experience they possibly could have. Then just moving past experience and drinking or putting the pacifier in their mouth again.